Alternator size

[BeatCJ]

I'm pretty sure I need to replace my alternator, multi-meter reads 12.07 running after reading 12.6 sitting. I do need to test the alternator hot wire to make sure it's not just the fusible link, I intend to replace that wire, but I'm waiting on an Amazon Fuse Holder.

Does anyone know if the 105 amp alternator will physically fit in the same bracket as the OEM 61 amp alternator? I ran into an issue with my 2001 GMC, it bolted in, but the taller alternator required a different serpentine belt. 

[Eagle]

The factory parts manual only shows 60, 85, and 100 amps. I think anything larger than that is an interference fit (i.e. won't physically fit the space). I don't remember the specifics but when I had the alternator for my '87 rebuilt, the guy initially said he could modify it for higher output, then he said the higher output parts needed a larger housing and he couldn't do the upgrade.

 

[BeatCJ]

I'm looking at NAPA, O' Reilly's and AutoZone, I believe stock alternators. One of the sites is showing two different body diameters. It seems like either will fit. I figure jumping from a stock 60 to stock 100 should be relatively simple, original wiring should work and all that jazz. I'll probably TOFTT and just give it a try, only one way to learn.

[JMO413]

I replaced a 60 and with a 100 amp.

[BeatCJ]

Good to hear, I have a 100 amp alternator in hand. I probably can't get to it until this weekend.

[schardein]

I have some brief notes on an 136 amp alternator upgrade, from 97-98 Dodge Durango & Jeep Grand Cherokee, OEM part number 56027913, alternate number 0280155703.

 

I ran this on the 91 XJ motor I put in my CJ7 from 1998-2014.  At some point I switched out the XJ bracket for a YJ bracket, and I can't remember if the 7913 alternator fit the factory XJ mount or not.  It's just been to long, I can't remember, but I want to say it's a bolt in.

 

EDIT: I think the alternator bolted in, but the pulley had 7 grooves, versus 6 for the XJ/MJ.  I used it anyway, with a gap at the front, with no issues for over a decade before swapping a 6 groove pulley onto the alternator.

[BeatCJ]

Good information, thanks

[ghetdjc320]

6 hours ago, schardein said:

I have some brief notes on an 136 amp alternator upgrade, from 97-98 Dodge Durango & Jeep Grand Cherokee, OEM part number 56027913, alternate number 0280155703.

 

I ran this on the 91 XJ motor I put in my CJ7 from 1998-2014.  At some point I switched out the XJ bracket for a YJ bracket, and I can't remember if the 7913 alternator fit the factory XJ mount or not.  It's just been to long, I can't remember, but I want to say it's a bolt in.

 

EDIT: I think the alternator bolted in, but the pulley had 7 grooves, versus 6 for the XJ/MJ.  I used it anyway, with a gap at the front, with no issues for over a decade before swapping a 6 groove pulley onto the alternator.

That’s what I currently run. Also use an external regulator and bumped the voltage to 14.4 since I have a lot of electrical components to run (triple 10 fans, electric brake booster, leds and more). Works great for me and took just a little bit of grinding to get it to fit

[schardein]

5 hours ago, ghetdjc320 said:

That’s what I currently run. Also use an external regulator and bumped the voltage to 14.4 since I have a lot of electrical components to run (triple 10 fans, electric brake booster, leds and more). Works great for me and took just a little bit of grinding to get it to fit

That's a great point, it's important to point out this alternator is regulated by the HO computer.  Swaps into a Renix originally equipped with an internally regulated alternator would require an external regulator.

[ghetdjc320]

1 hour ago, schardein said:

That's a great point, it's important to point out this alternator is regulated by the HO computer.  Swaps into a Renix originally equipped with an internally regulated alternator would require an external regulator.

 

I’m running the HO computer on my 91 but wanted more voltage than the stock ecu settings allow. As you mentioned, for renix it’s a must. It’s a simple setup too. Easy to install and configure

[70barracuda]

I used a 105 amp off a Caprice with the cop car specs. Bracket had to be trimmed a bit and I did reclock it so the power stud was in a better spot. Took me like maybe an hour and it fit perfect. Plugs right in. 

[BeatCJ]

I left work an hour early, got the alternator swapped in. The 100 amp optional alternator fits just fine. Interesting thing, the sticker on the side says 100 amps at 6000 rpm, 79 amps at 2000 rpm. I ASSUME that's alternator rpm, not crank rpm. I hope my 4.0 never sees 6000 rpm.